package org.gthelper.security;

//import java.io.OutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;


public class IdentityRSA implements Iidentity
{
	
	
		//非对称加密密钥算法
		private static final String KEY_ALGORITHM = "RSA";
		//公钥
		private static final String PUBLIC_KEY = "publickeykey";
		//私钥
		private static final String PRIVATE_KEY = "privatekeykey";
		//密钥长度，必须为64的倍数,默认1024
		private static final int KEY_SIZE = 2048;
		//数字签名、验证算法
		private static final String SIGNATURE_ALGORITHM = "SHA1withRSA";
		
		
//		/**
//		 * 信息摘要
//		 * @param data
//		 * @return 摘要数据
//		 * @throws Exception
//		 */
//	public byte[] encryptSHA(byte[] data) throws Exception {  
//	
//		MessageDigest sha = MessageDigest.getInstance(KEY_SHA);  
//	    sha.update(data);  
//	  
//	    return sha.digest(); 
//	}  
		
	
	
	/**
	 * 初始化密钥
	 * 
	 * @return Map 密钥Map
	 * @throws Exception
	 */
	public Map<String, Object> initKey() throws Exception {

		// 实例化密钥对生成器
		KeyPairGenerator keyPairGen = KeyPairGenerator
				.getInstance(KEY_ALGORITHM);

		// 初始化密钥对生成器
		keyPairGen.initialize(KEY_SIZE);

		// 生成密钥对
		KeyPair keyPair = keyPairGen.generateKeyPair();

		// 公钥
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

		// 私钥
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

		// 封装密钥
		Map<String, Object> keyMap = new HashMap<String, Object>(2);

		keyMap.put(PUBLIC_KEY, publicKey);
		keyMap.put(PRIVATE_KEY, privateKey);

		return keyMap;
	}
	
	
	
	/**
	 * 取得私钥
	 * 
	 * @param keyMap
	 *            密钥Map
	 * @return byte[] 私钥
	 * @throws Exception
	 */
	public byte[] getPrivateKey(Map<String, Object> keyMap)
			throws Exception {

		Key key = (Key) keyMap.get(PRIVATE_KEY);

		return key.getEncoded();
	}
	
	
	/**
	 * 取得公钥
	 * 
	 * @param keyMap
	 *            密钥Map
	 * @return byte[] 公钥
	 * @throws Exception
	 */
	public byte[] getPublicKey(Map<String, Object> keyMap)
			throws Exception {

		Key key = (Key) keyMap.get(PUBLIC_KEY);

		return key.getEncoded();
	}

	
	
	
	/**
	 * 私钥加密
	 * 
	 * @param data
	 *            待加密数据
	 * @param key
	 *            私钥
	 * @return byte[] 加密数据
	 * @throws Exception
	 */
	public byte[] encryptByPrivateKey(byte[] data, byte[] key)
			throws Exception {

		// 取得私钥
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(key);

		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

		// 生成私钥
		PrivateKey privateKey = keyFactory.generatePrivate(pkcs8KeySpec);

		// 对数据加密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

		cipher.init(Cipher.ENCRYPT_MODE, privateKey);

		return cipher.doFinal(data);
	}
	
	
	/**
	 * 公钥加密
	 * 
	 * @param data
	 *            待加密数据
	 * @param key
	 *            公钥
	 * @return byte[] 加密数据
	 * @throws Exception
	 */
	public byte[] encryptByPublicKey(byte[] data, byte[] key)
			throws Exception {

		// 取得公钥
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(key);

		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

		PublicKey publicKey = keyFactory.generatePublic(x509KeySpec);

		// 对数据加密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

		cipher.init(Cipher.ENCRYPT_MODE, publicKey);

		return cipher.doFinal(data);
	}
	
	/**
	 * 签名
	 * @param data
	 * @param privateKey
	 * @return 签名数据
	 * @throws Exception
	 */
	public byte[] sign(byte[] data, byte[] privateKey) throws Exception {

		// 取得私钥
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(privateKey);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);

		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);

		// 初始化Signature
		signature.initSign(priKey);
		
//		byte[] shaData = encryptSHA(data);
		
		// 更新
		signature.update(data);

		// 签名
		return signature.sign();
	}

	
	
}